The invention relates to a starting and stopping device for an internal combustion engine. More specifically, the present invention relates to a mechanism for starting the engine by unloading stored power in an elastic member.
The invention provides an internal combustion engine comprising an engine housing, a crankshaft mounted for rotation within the engine housing, a flywheel mounted to the crankshaft for rotation therewith in a starting direction during startup and operation of the engine, and a spring housing rotatably mounted to the engine housing. An energy storing mechanism, including at least one elastic member, is housed within the spring housing. The elastic member is loaded in response to the spring housing rotating in a loading direction, and the spring housing rotates in an unloading direction opposite the loading direction in response to unloading of the elastic member.
The engine also includes a spring loading mechanism including at least one roller movable into and out of engagement between the flywheel and the spring housing, such that rotation of the flywheel in the starting direction is converted through the at least one roller into rotation of the spring housing in the loading direction.
An engine starting mechanism is also provided that preferably includes a helically threaded member interconnected with the spring housing, and a starter pinion threaded onto the helically threaded member, such that rotation of the spring housing in the unloading direction causes the starter pinion to move into engagement with the flywheel. The starter pinion thus converts rotation of the spring housing in the unloading direction into rotation of the flywheel in the starting direction to start the engine. The starter pinion may be a friction roller or a toothed gear. A control system is also provided for releasing the elastic member from a loaded state to cause rotation of the spring housing in the unloading direction.
Preferably, the above-described at least one roller includes a first roller movable into and out of engagement with the flywheel and a second roller movable into and out of engagement with the spring housing. The first and second rollers are preferably coupled for rotation together such that rotation of the flywheel in the starting direction is converted through the first and second rollers into rotation of the spring housing in the loading direction.
An overwind clutch may be operatively disposed between the first and second rollers to couple the first and second rollers for rotation together. When a threshold torque is achieved between the first and second rollers (i.e., when the stored load in the elastic member reaches a high level), the overwind clutch will permit relative rotation between the first and second rollers to reduce the likelihood of damaging the spring.
A one-way clutch is preferably used to either interconnect the elastic member with an arbor in the spring housing, or to support the arbor with respect to the engine housing. The one-way clutch reduces the likelihood of damage to the inner end of the elastic member during unloading.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings.